 The Hubble Space Telescope took this picture of Saturn on July 4, 2020, when the planet was just 1,350 million kilometers from Earth, that's 839 million miles. At that time, it was summer in the planet's northern hemisphere. The rings are mostly made of pieces of ice, with sizes ranging from tiny grains to giant boulders. That's how and when the rings formed remains one of our solar system's biggest mysteries. Conventional wisdom is that they are as old as the planet itself, around 4 billion years. We cover this in the How Old Is It video book. But a competing theory is that they may have formed more recently, during the past few hundred million years. The Cassini spacecraft measurements of tiny grains raining down from the rings into Saturn's atmosphere suggest the rings can only last for around 300 million more years. This is one of the arguments for a young age for the ring system.